The purpose of this study is: 1) To determine whether the use of antibiotics and tocolytics in patients with preterm labor will improve perinatal outcome as compared to use of tocolytics alone; i.e., is subclinical intraamniotic infection a factor in preterm labor. 2) To assess a scoring system for occult intraamniotic infection. 3) To assess whether interleukin-1 levels are predictive of subclinical infection and failed tocolysis.